1. Field of the Invention
This invention relates to seals and more particularly to rotating mechanical shaft seals.
2. Description of the Prior Art
Rotating mating face shaft seals having a rotating seal portion attached to a shaft and a non-rotating seal portion attached to a stationary housing surrounding the shaft with a face seal interposed between the two portions are known to the art. In addition, it has been known to spring back the rotating seal portion of the assembly while attaching the stationary portion of the sealing assembly to the housing through a resilient backing. See for example U.S. Pat. No. 3,020,052 to Gits. Additionally, it has been known to isolate the connection of the rotating shaft carried portion of the seal assembly from the connection to the shaft and to provide a floating face seal. See for example U.S. Pat. No. 3,420,535 to Hershey or U.S. Pat. No. 3,765,689 to Adams. Such special embodiment constructions have been created in an attempt to overcome face distortion at the interface of the seal. For example, the seal face can be distorted through the effect of the clamping operation which enclamps the seal face member to either the shaft or the housing. Attempts to avoid this distortion have led to the separation of the seal face carrying member from the enclamping member. Additionally, it has been known to attempt to provide for the establishment of a seal face perpendicular to the shaft by floating the seal face with respect to the shaft.
Such prior art attempts to eliminate seal interface problems have not been entirely successful, either because they have not sufficiently isolated the seal from the enclamping force or because they have not adequately provided for full float at the interface. In addition, seal face distortion is increased because of the necessity to urge the mating faces together with a pressure sufficient to prevent leakage. When this has been done, in the past, any distortion or non-perpendicular relation between the mating faces and the shaft or between the mating faces themselves has required an increase in spring force. The increase in spring force can, in certain embodiments, have an extremely disadvantageous effect upon both the life and performance of the seal as well as an additive effect to the distortion problem itself.
It would therefore be an advance in the art to provide a fully floating mechanical shaft seal where the main seal face is entirely free of clamping distortions while being equally free to align itself perpendicularly to the shaft.